The evolution of ‘Man’: Hard science and human masculinity

Most informed readers are probably comfortable with the idea that there are multiple cultural constructions of masculinity, but some may be less cosy with biological or evolutionary perspectives on this topic. For decades now, political progressives have, quite rightly, fought to establish a constructivist view of sex and gender, one which allows for more varied expressions of human self-identity. As such, it may seem that biological perspectives would promote only a regressive, perhaps offensive or even oppressive viewpoint.

However, any complete study of humanity must embrace both cultural and biological influences. Although past depictions of human existence were often based on a theoretical separation between culture and biology, this idealised division cannot exist in reality. It follows that biological and evolutionary insights can shed light on aspects of human masculinity that are not apparent from social or psychological analysis alone.

For example, whilst many popular narratives regarding the evolution of ‘Man’ have idealised a rugged, competitive and aggressive masculinity as the secret to our species’ evolutionary success, fossil analysis shows that recent human evolution involved an overall reduction in physical masculinity. Considering the implications of this declining evolutionary trajectory provides a broader perspective of human masculinity and its apparent fluidity on several levels.

In popular online discourse simplistic depictions of our evolutionary past are often used to support various assertions about ‘human nature’, as well as normative assumptions of the ‘naturalness’ of heterosexuality and binary gender roles assigned to men and women. In fact, most evolutionary discussion is inclined towards hetero and binary perspectives, perhaps because, at least among sexually reproducing organisms, all ‘descent with modification’ involves the joining of sperm and ova. However, these facts of life cannot be used to deny the widespread presence of non-heterosexual preferences and non-binary identities among a considerable proportion of humanity—and in other sexual species too.

Aside from expressions of sexuality and gender, biological sex itself is far more fluid than simplified evolutionary narratives generally allow. As many as two percent of humans do not conform to binary sexual ideals at birth—that is, they are neither ‘perfectly male’ nor ‘perfectly female’, but simply themselves. This shows that instead of conforming to an idealised binary based on sperm and ova, human sexual biology operates as a continuum—some say more like a dial than a switch; others suggest a spectrum, or mosaic, of difference.

These observations provide objective scientific support for the politics of gender and self-identity underpinning recent social programs like ‘Safe Schools’ in Australia, as well as similar initiatives in other parts of the world. Statistics on human intersexuality show that claims for the naturalness, moral superiority or divine sanctity of ‘traditional’ sex and gender roles are only so much ideological hot air. Despite regular assertions that the proponents of programs like Safe Schools are pushing an ideological position, the science says otherwise. Humans are biologically non-binary.

This is not to discount the existence of people who do identify as male or female, or to suggest that there are no generalisable differences between these two sexes. However, it does help to expand our views on the wider possibilities of human being. What’s more, it emphasises the logical inadequacy of any cultural construction which idealises male and female as naturally dualistic opposites. An orange is not the opposite of an apple. Nor is a sperm the opposite of an ova. Physically and behaviourally, men are not the opposite of women, nor women the opposite of men. As such, any construction of masculinity which requires a diametrically opposing form of femininity is an unrealistic mental fabrication.

Whilst some may argue that people have a right to unrealistic mental fabrications, especially in regard to their own self-identity, this is true only if opinions based upon those fabrications are not expressed in the real world. Anyone choosing to impose their unrealistic views upon the rest of us should expect to have them challenged and dismissed; especially where such views impinge upon the freedom and equality of others.

Biological science has demonstrated a great deal about the phenomenon of human masculinity. At a basic level, we know that certain physiological characteristics are more often associated with males than with females. Typically-masculine traits include things like: large brow ridges, a large jaw, a deep voice, broad shoulders, and general bodily and facial hairiness. Especially-masculine individuals tend to have higher testosterone levels, are anatomically larger, are taller overall, are heavier, more muscular and have denser, stronger bones.

As with sex and gender, physical masculinity occurs as a continuum, or spectrum of expression, not as a binary. Not all men show elevated levels of masculinity. Some show low levels, while the majority are only moderately masculine. Also, some women show more physical masculinity than some men. In spite of this variation, however, science tends to emphasise generalisable, not absolute, differences. So, if a characteristic is shown to be mainly associated with males, it tends to be referred to as a masculine trait.

The existence of masculine physical traits must influence people’s personal self-identities as well as socially accepted forms of masculine self-expression. Overtly masculine features appear regularly in cultural representations of the male form and will, therefore, affect our views on what it means to be a man. Beyond these cultural influences, however, there is also evidence to suggest that human behaviour can be directly affected by aspects of masculine physiology. Physically masculine traits tend to correlate with higher levels of masculine hormones (e.g. testosterone) and these hormones are associated with certain behaviours, especially, though not exclusively, among males.

For example, in both human and non-human primates, high testosterone has been linked to higher reproductive effort; that is, more time and energy spent pursuing opportunities for sex. One particularly famous study found that men with higher testosterone levels were less likely to marry and, when they do marry, their unions were more likely to involve infidelity, conflict and intimate partner violence, as well as to end in divorce.

High-testosterone males have also been found to be more competitive and more likely to commit violent crime. The period in life between eighteen and twenty-five, when young men are most likely to commit antisocial and violent acts, or to die from risk-taking behaviour, also corresponds with physiological peaks in testosterone. High testosterone doesn’t cause antisocial behaviour, but there is an association. Given this, it seems unlikely that statistical differences in male and female antisocial acts (see here and here) result entirely from socially constructed genders. Social factors are a major influence, but this doesn’t mean that evolved sexual difference evaporated as humans developed their capacity for complex culture.

Having said this, sexual differences have notably reduced throughout human evolution. Our relatively recent male ancestors, though still classified as Homo sapiens, were, on average, significantly more masculine and physically robust than males are today. Viewed from an evolutionary perspective, masculinity appears to be declining. This is certainly true over the last 200,000 years, and some argue it has continued across more recent history too.

It’s been suggested that these declines in masculinity were a necessary precondition to the emergence of complex human societies and civilisations. As average masculinity diminished, humans became relatively less aggressive and more sociable. Increased sociability allowed for more sustained and harmonious interaction between individuals, leading to greater social complexity and cooperation. In turn, this promoted the development of language, greater knowledge sharing and increased technological innovation.

Debate continues over the pre-historic drivers of this masculinity decline. Some authors suggest that social benefits, like reciprocal food sharing or support in conflict, would be enough to advantage more-sociable, less-masculine males. Others believe that human groups naturally ostracise the most antisocial (hence, most physiologically masculine) individuals, thereby lowering those individuals’ chances of survival and reproduction. The invention and use of weapons and projectile hunting tools rather than hand-to-hand combat and close-in big-game hunting are further plausible reasons suggested by some. Still others suggest women’s socio-sexual preferences for low, or moderate, masculinity as a possible cause. A related possibility is that increasing human altriciality (the helplessness of newborns) advantaged less-masculine males since they were less likely to pursue multiple partners and more likely to invest support toward offspring survival.

Whatever the specific mechanisms—and it could well have been all of the above—human evolution has favoured the emergence of a diversity of physiologies, with an accompanying overall decline in average masculinity and an increase in sociability. We may not have perfected our transition to sociability, but our evolutionary trajectory is clear. Decreasing masculinity made us better adapted to a complex and cooperative sociocultural niche. Today, we owe our survival to our capacity to get along with others.

This observation contrasts with dated popular notions that ‘Man’ survived because of ‘his’ ability to make fire, kill mammoths and club women over the head. But despite the ongoing fantasies of macho survivalists, and economists’ idealised fairy-tales about ‘rational self-interested individuals’, we have long been a hyper-cooperative and social species. Why? Because this strategy pays better in terms of survival and reproduction than any isolated and rugged individualism ever could.

So, while we discuss and debate our diverse cultural and personal constructions of masculinity, it’s worth bearing in mind that the evolutionary evidence also suggests a certain fluidity. What it means to be a man has changed, across history and prehistory, in both cultural and biological terms. Humanity’s recent technological and cultural success required a substantial decrease in physiological masculinity, with concurrent increases in sociability and cooperative capacity.

These observations contradict narratives which idolise the evolutionary supremacy of rugged masculine individualism whilst portraying the non-masculine as either inferior (women and other males) or deviant (non-binary identifying). We need to incorporate new, science-based perspectives of masculinity within our constructed masculine self-identities, whilst learning to value and embrace quintessential human diversity and sociability. Today, and in future, each of us must make space for all forms of human being, and should work to prevent antisocial constructions of ‘Man’ and masculinity from undermining the cooperative basis of our collective survival.

Header photo by Sidney Perry.

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